High Production of β-Glucosidase in Schizophyllum commune : Isolation of the Enzyme and Effect of the Culture Filtrate on Cellulose Hydrolysis

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Abstract
Optimization experiments with response surface statistical analysis were performed with Schizophyllum commune to obtain high β-glucosidase yields. The factors in the optimization experiment were the concentrations of cellulose, peptone, and KH 2 PO 4 . Their optimal values were 3.2, 3.0, and 0.2 g/100 ml, respectively. Enzyme assays revealed very high β-glucosidase (22.2 U/ml) and cellobiase (68.9 U/ml) yields. The avicelase yield was low as compared with that from Trichoderma reesei . Mixtures of S. commune and T. reesei culture filtrates caused faster and more extensive saccharification of Avicel than could be achieved by either filtrate alone. A β-glucosidase was isolated and purified from the optimized culture filtrate of S. commune . The electrophoretic mobility of the purified β-glucosidase indicated a molecular weight of 97,000. The amino acid composition was similar to that of β-glucosidase from T. reesei . The acidic (aspartate and glutamate) residues or their amides or both made up approximately 20% of the protein. The NH 2 -terminal amino acid of the enzyme was histidine.